Climate

climate

During the last 2.5 million years, Earth’s climate has seen cycles of advancing and retreating glaciers over much of the Northern Hemisphere. We are currently in a warm, interglacial period — one that’s been prolonged by increases in atmospheric concentrations of greenhouse gases, such as carbon dioxide and methane. According to a new study in Nature, these high concentrations of greenhouse gases have disrupted the recent pattern of cycling in Earth’s climate and pushed back the next ice age. The study also suggests that human activity, beginning thousands of years ago with early agriculture and continuing through to the present day, has fueled the rise in greenhouse gas concentrations.

About 8,200 years ago, right around the time that animals such as cows and sheep were first being domesticated in the Near East for meat and milk, the planet underwent a cooling event that lasted about 160 years. How this cold snap, known as the 8.2-kiloyear event, affected early farmers has long been a mystery, as archaeological evidence from the period of the cooler and drier climate has been scant. But new research investigating fatty residues preserved on scraps of pottery found at the UNESCO World Heritage site of Çatalhöyük in Turkey is offering some clues.

After warming the bench since the Pleistocene, a key player in the Arctic carbon cycle is getting back in the game thanks to thawing permafrost. In a new study, researchers report that rising temperatures are freeing sulfide minerals previously bound within Arctic permafrost. These minerals are contributing to stream acidification and accelerated weathering of carbonates — and thus to the release of carbon dioxide into the atmosphere — at least in one part of northern Canada.

Coastal Southern California is famous for cloudless blue skies all summer long, but it hasn’t always been that way. A new study indicates that cloud cover has decreased dramatically over the beaches between Los Angeles and San Diego since the 1970s. And that could affect fires in the region.

The Mississippi River is notorious for flooding its muddy banks, with many critical areas actively managed by the Army Corps of Engineers to control flooding. But despite all the controls, major floods still occur.

The landscape and culture of Iceland, more so than any other country, have been shaped by volcanism. In a new study, researchers have refined the dates for the massive 10th-century Eldgjá eruption, which occurred just a few decades after the island was first settled. The findings may support a connection between the violent volcanism depicted in Iceland’s most celebrated medieval poem and the island’s conversion from paganism to Christianity.

Scientists have long assumed that temperature is the main control on melting of winter snowpacks across the mountainous western United States. In a recent study, however, scientists suggest that regional humidity may have a larger impact than temperature.

In January 2017, skiers at Wolf Creek Ski Area in southern Colorado were enjoying a base snow depth of more than 350 centimeters — enough snow to cover most rocks and other obstacles. But this year, as of mid-January, the runs were much sparser, with the base barely clearing 100 centimeters. Powderhorn Resort in western Colorado was so bereft of snow that it had yet to open in mid-January — a month behind their usual December opening. Statewide the snowpack is slim enough to worry not only skiers, but also the state’s climatologists and water resource managers, who held a Water Availability Task Force (WATF) meeting on Jan. 18 to discuss the state’s snowpack and water outlook.